#2 - A large number of drivers routinely violate highway

[silent7706]

Hi,

Negation of (A): A person needs to be a trained mechanic to install the device properly.

Will the negation of (A) weaken the effectiveness of the proposal (installing devices in all cars...) if we were dealing with a weakening question?

Thanks in advance.

[Adam Tyson]

I think not, silent7706, because we would have no reason to believe that anyone other than trained mechanics would be installing the devices. To weaken this argument, we would look for some claim that suggests that installing the devices won't have that effect, rather than something that indicates a level of difficulty in installing them in the first place.

[MeliXi]

hello;

can someone please provide a better explanation for why C makes sense?
why would a driver even speed to avoid an accident? where is this even coming from? how do we go from speeding causes accidents to speeding in order to avoid accidents? if I were thinking about assumptions just by reading the stimulus, speeding to avoid accidents wouldn't even have been something that I thought of.
I chose E as my answer but I read the explanations & now understand why it's not E. However, I'm still quite confused about the appropriate thought process in determining C as the correct answer.

[KelseyWoods]

Hi MeliXi!

Correct answers in assumption questions are not always going to be things we specifically thought of when reading the argument--especially when it comes to Defender Assumptions like this one! But they will always be something that is necessary for the conclusion stated to follow from the premises given. So always start there. Specifically identify what the conclusion is and what the premise is:

Premise: driving at speeds that exceed posted limits is a significant factor in most accidents
Conclusion: installing devices in all cars that prevent those cars from traveling faster than the speed limit would prevent most accidents

The author is telling us that most accidents involve excessive speed and then concluding that therefore we could prevent most accidents by preventing cars from driving faster than the speed limit.

There's not a clear gap between the premises and the conclusions in this argument, like we frequently see when the correct answer ends up being a Supporter Assumption. But there are some potential weaknesses here. Would preventing cars from driving above the speed limit really prevent most accidents? Is there any scenario in which driving above the speed limit might be necessary to prevent an accident? This argument is a prime candidate for a Defender Assumption.

The Assumption Negation Technique is especially helpful on Defender Assumptions (because sometimes they feel like they come out of nowhere!) so let's try it out on answer choice (C): "A driver seldom often needs to exceed the speed limit to avoid an accident when none of the other drivers involved are violating the speed limit."

If a driver often needs to exceed the speed limit to avoid an accident that doesn't involve excessive speed (for example, think speeding up to pass a drunk/texting driver who is swerving into your lane), then installing a device that prevents all drivers from exceeding the speed limit might prevent the crashes that are caused by excessive speed but end up causing a whole bunch of crashes that previously could have been avoided. Thus, answer choice (C) is a Defender Assumption that defends the argument from this particular source of attack by saying, no, that doesn't happen. Drivers don't really need to be able to speed to avoid accidents.

Hope this helps!

Best,
Kelsey